Method of fabricating thin O/N/O stacked dielectric for high-density DRAMs

Abstract

A method of fabricating a super thin O/N/O stacked dielectric by oxidizing a thin nitride layer in low pressure oxygen for high-density DRAMs is disclosed. A thin nitride layer with a thickness of approximately 20 Å to 60 Å is formed over the surface of a silicon substrate. The nitride layer is oxidized in pure oxygen ambient of 0.01 Torr to 76 Torr at a temperature from 750° C. to 950° C. for approximately 10 to 60 minutes. A super thin oxide/nitride/oxide (O/N/O) stacked dielectric exhibiting a low leakage current and high reliability for use in high-density DRAMs is formed by the aforementioned low-pressure dry-oxidation procedure.

What is claimed is: 
     
       1. A method of fabricating an O/N/O stacked dielectric on a silicon substrate, comprising the steps of: (a) forming a nitride layer on a surface of said silicon substrate wherein said nitride layer has a thickness between 20 Å and 60 Å; and   (b) oxidizing said nitride layer in pure oxygen ambient of 0.01 Torr to 76 Torr at a temperature between 750° C. and 950° C. for approximately 10 to 60 minutes to form an oxide/nitride/oxide (O/N/O) stacked dielectric on said substrate.   
     
     
       2. The method of claim 1 wherein said nitride layer has a thickness of approximately 42 Å and is oxidized at a temperature of approximately 850° C. for approximately 30 minutes at approximately 0.1 Torr.